Horsetan Posted July 14, 2015 Share Posted July 14, 2015 Says the second man known as I can't sleep as I've a Deltic and Western going around in my head. I'm a secret lemonade drinker as well, Ozzy. Looks like it's gonna be one of those nights... Link to post Share on other sites More sharing options...
sej Posted July 14, 2015 Share Posted July 14, 2015 Hi Andrew: That's a beautiful build, thanks for the added information. Could you expand a little on your Slater's wheel upgrades? With pictures? Where do you get the telescopic axlesand do you turn the wheel profile at all? And, if you were building an LMS Duchess do you have a method for at least hinting at the hollow axles? I'm asking that because I will eventually get around to building my "City of St Albans" and I do like a hollow axle... Cheers Simon Link to post Share on other sites More sharing options...
Funtleyworks Posted July 14, 2015 Share Posted July 14, 2015 Hi Andrew: That's a beautiful build, thanks for the added information. Could you expand a little on your Slater's wheel upgrades? With pictures? Where do you get the telescopic axlesand do you turn the wheel profile at all? And, if you were building an LMS Duchess do you have a method for at least hinting at the hollow axles? I'm asking that because I will eventually get around to building my "City of St Albans" and I do like a hollow axle... Cheers Simon Hello Simon Many thanks for your kind comments. The axles are just 3/16 nickel silver drilled 5/32 to mount the male part of the wheel. I remove the brass hub containing the square hole then mount them on tufnol bushes. The wheels are then mounted and pinned on them. I also remove about 1mm from the back of the wheel to give the spokes a more slender appearance. I do reduce the wheel profile to if needed for clearance problems with brakes etc and to make the wheel look nicer!! And also scale 7 profiles are catered for!! Crankpins are replaced with Derek Mundy's lovely product to! Hollow axles are not a problem, but I only drill about 10mm in, but you could drill all the way through if needed, but the taper pin would be visible if you looked direct at the end of the wheel. Have included a picture of a Finney Coronation that I built, but cant claim credit for the loco body as that was built by the customer!!! It has Harris wheels I turned with a hollow axle, but not all way through!! ATB Andrew 3 Link to post Share on other sites More sharing options...
Tim2014 Posted July 14, 2015 Author Share Posted July 14, 2015 Hello Simon Many thanks for your kind comments. The axles are just 3/16 nickel silver drilled 5/32 to mount the male part of the wheel. I remove the brass hub containing the square hole then mount them on tufnol bushes. The wheels are then mounted and pinned on them. I also remove about 1mm from the back of the wheel to give the spokes a more slender appearance. I do reduce the wheel profile to if needed for clearance problems with brakes etc and to make the wheel look nicer!! And also scale 7 profiles are catered for!! Crankpins are replaced with Derek Mundy's lovely product to! Hollow axles are not a problem, but I only drill about 10mm in, but you could drill all the way through if needed, but the taper pin would be visible if you looked direct at the end of the wheel. Have included a picture of a Finney Coronation that I built, but cant claim credit for the loco body as that was built by the customer!!! It has Harris wheels I turned with a hollow axle, but not all way through!! ATB Andrew Thanks so much for your answers to my questions. After posting I thought the smokebox might be an anchor point. I'll have to give it some serious thought. I've probably not been thinking about painting as much as I should. I have a pretty decent airbrush and mostly we get on OK. I'd say my painting is better than my soldering (lining is a different matter) so I'm planning to do it myself and the attraction of separating the boiler is clear. Now is the time for others to tell me I'll be fine just whacking it all together and painting once fully assembled - or not! And the education about hollow axles is helpful as I intend to try my hand at a Duchess sometime in the future (my favourite looking loco by some way). I figured it was a little too ambitious to start with one of them! Drilling an axle is beyond my machining capabilities and tooling at the moment, I lack even a drill press so I will have to either compromise, or buy in components. I can't see myself ever making enough models to justify buying good tools and a workshop to use them in. So I'll toddle off and start buffing up those coupling rods with the wet and dry then, I was sort of hoping you'd declare they were very expensive add-ons too to let me off the hook (I'd rather have two OK locos than one superb one, though if I can improve the OK ones on the cheap with my lack of tooling and skills, even better!) 1 Link to post Share on other sites More sharing options...
Funtleyworks Posted July 14, 2015 Share Posted July 14, 2015 Thanks so much for your answers to my questions. After posting I thought the smokebox might be an anchor point. I'll have to give it some serious thought. I've probably not been thinking about painting as much as I should. I have a pretty decent airbrush and mostly we get on OK. I'd say my painting is better than my soldering (lining is a different matter) so I'm planning to do it myself and the attraction of separating the boiler is clear. Now is the time for others to tell me I'll be fine just whacking it all together and painting once fully assembled - or not! And the education about hollow axles is helpful as I intend to try my hand at a Duchess sometime in the future (my favourite looking loco by some way). I figured it was a little too ambitious to start with one of them! Drilling an axle is beyond my machining capabilities and tooling at the moment, I lack even a drill press so I will have to either compromise, or buy in components. I can't see myself ever making enough models to justify buying good tools and a workshop to use them in. So I'll toddle off and start buffing up those coupling rods with the wet and dry then, I was sort of hoping you'd declare they were very expensive add-ons too to let me off the hook (I'd rather have two OK locos than one superb one, though if I can improve the OK ones on the cheap with my lack of tooling and skills, even better!) Hello Tim! Sorry for hijacking your post! Without a doubt making the parts separate for painting I believe is not essential but if you can make them separate then go for it. Most of the time it is not that complicated either. The holes in the cab and firebox are already there!! I can't remember quite how I fixed the front to the frame but I think I just drilled and tapped through the smokebox. When it comes to painting if the boiler/firebox assembly is separate then it makes spraying easier, for example that point where the firebox meets the cab front instead of trying to spray into a 90 degree corner and overloading with it paint you just have a clear pass to make across parts. As for the coupling rods the Jubilees I built had them expensive premier components, and although nice I didn't really feel they were quite worth the expense!! 3 Link to post Share on other sites More sharing options...
sej Posted July 14, 2015 Share Posted July 14, 2015 Cheers Andrew: Excellent information on improving Slater's wheels, I'll have a go at some axles for my next 7mm build, which after looking at your beautiful Duchess will probably be one of those! Many thanks again. Simon 1 Link to post Share on other sites More sharing options...
Tim2014 Posted July 17, 2015 Author Share Posted July 17, 2015 Hello Tim! Sorry for hijacking your post! Without a doubt making the parts separate for painting I believe is not essential but if you can make them separate then go for it. Most of the time it is not that complicated either. The holes in the cab and firebox are already there!! I can't remember quite how I fixed the front to the frame but I think I just drilled and tapped through the smokebox. When it comes to painting if the boiler/firebox assembly is separate then it makes spraying easier, for example that point where the firebox meets the cab front instead of trying to spray into a 90 degree corner and overloading with it paint you just have a clear pass to make across parts. As for the coupling rods the Jubilees I built had them expensive premier components, and although nice I didn't really feel they were quite worth the expense!! Not at all! Great to see beautiful models of LMS locos, especially when accompanied by useful advice. Your idea of building the boiler detachable would *never* have occurred to me and as I think about it more, the more I think I will follow suit. There's a little additional complexity, but as you say, very little really for the benefits gained, and nothing compared to building valve gear. I have to say that I agree about the benefits of milled rods, noting that I've not seen that many examples, and at the end of the day a lot of it is personal choice. You can do a lot with careful assembly of etchings, especially if you don't mind adding a bit of scratch building. I think there are other things I'd spend money on first (like working reversing gear, ha, ha!) - especially as you can always upgrade the motion down the track if you really wanted to. Thanks for stopping by and providing guidance and inspiration. 1 Link to post Share on other sites More sharing options...
Tim2014 Posted July 17, 2015 Author Share Posted July 17, 2015 Cheers Andrew: Excellent information on improving Slater's wheels, I'll have a go at some axles for my next 7mm build, which after looking at your beautiful Duchess will probably be one of those! Many thanks again. Simon And please post a build thread so I can follow it Link to post Share on other sites More sharing options...
Tim2014 Posted August 5, 2015 Author Share Posted August 5, 2015 (edited) Sorry, it’s been a while, I’ve not been modeling as much recently, but I have been making progress. The RHS valve gear is taking shape. I’ve realized that I glossed over what I did to the LHS, so since this is supposed to be a build thread, I’ll explain what I did and the pitfalls I fell into. It’ll bore those who’ve built more models than I’ve had hot dinners, but it might help some other newbies like me someday. The stock expansion link in this kit is basic so I decided to thicken it by adding an extra face to each side. Two scrap pieces of N/S were rough cut and then soldered to the grooved pieces. You actually want to see the join based on the prototype pics and too much solder will flood the groove, so I used it sparingly. I don’t have scale drawings of this part so relied on the kit part and photos to give me what I hope is a passing resemblance. I added a pin to the radius rod and checked it was a fairly sloppy fit in the expansion link groove. Now you may recall I wanted to have a controllable, fully moving reverse gear. I did get as far as figuring out how to do it, but the final straw was realizing the expansion link groove isn’t actually long enough to allow full reverse, so for the sake of my sanity, and until I figure how much space I have to play with, and in the interests of actually getting a finished model, I'm fixing the loco in forward gear (these pics make it look like it's fixed in neutral, it's not, the radius rod is free to travel in the groove below the pivot pin). The final step (not really shown) is to solder the stud of a 14 BA bolt onto the inside face to make it easier to screw on the 14BA nut, that might not make it into the final version, but it does help with getting everything in place. In folding the link up together, it will inevitable start to fatigue along the half etch fold lines so a dab of solder on one side will hold the top of the link on which is useful to keep the sides at the right spacing around the radius rod. There was some discussion earlier about return cranks. Here’s the method I used, a 10BA tapped Slaters top hat bush is soldered to the plain etch, then fitted to the 10 BA bolt thru the wheel to see how much to file the bolt down, it mustn’t be proud of the crank when done up into the right position (now is a good time to rotate the bolt head in the wheel back to make sure the return crank is a good tight fit when screwed onto the coupling rod top hat bush (which is drilled out to take the 10BA bolt and freely rotate): Then the top face is soldered on, and a rivet added. Bingo! A return crank and ‘nut’ for the coupling rod in one. Time will tell if it needs threadlocker, I’ll try without first. My version of the eccentric rod has two bosses added, the inner one gives some much needed clearance over the return crank while the outer adds the thickness that is visible in the prototype. I haven’t yet got the rod edges polished up to my satisfaction, this is just 'as filed', the wet and dry will come out before I blacken it all. Next post I’ll show some of the clearance issues I’ve had and how I’ve got around them. At the time I thought I’d done something wrong, or the kit design was a bit off, but I’ve since realized that my ‘solutions’ are evident on the prototype too! Edited August 5, 2015 by Tim2014 3 Link to post Share on other sites More sharing options...
Grasshopper John Posted August 6, 2015 Share Posted August 6, 2015 Tim, make sure the return crank is 5-10dg forward facing when the crankpin is at 6oc. Link to post Share on other sites More sharing options...
Tim2014 Posted August 10, 2015 Author Share Posted August 10, 2015 Thanks John, that's really helpful. I've not loctited the 10BA crankpins in place yet, so can still adjust, but by eye it's close - and there's a reasonable amount of wiggle room in the tightening as with any torque system. I guess too far and I'll strip the top-hat or (more likely) twist the crankpin in the wheel. It's not *that* hard to get to the screw now, so that would be inexcusable, but I'm thinking about later when I do it for the last time with loctite. The only downside I can think of with this method is that making up a new return crank for whatever reason, would need some pretty nifty soldering as you work out the orientation of the new top hat on the crankpin, then solder it on at exactly that angle onto the first (plain) lamination of the return crank. I can't see how you could properly torque up the top-hat without the return crank attached so there'd be a few iterations of solder, fit, swear, desolder, twist, resolder etc. to get it right. I'm trying to worry about that less and less, but it's certainly handy at the moment, disassembly is a snap and allows all the motion bar the coupling rods to come off in one unit. Link to post Share on other sites More sharing options...
Pete Harvey Posted August 10, 2015 Share Posted August 10, 2015 Hi Tim "I've not loctited the 10BA crankpins in place yet" Don't use loctite as the only way to remove them if you have to would be to over heat the loctite to release it's hold use some paint as it will do the same job but you won't have to destroy you model to remove the parts. Pete Link to post Share on other sites More sharing options...
Tim2014 Posted August 10, 2015 Author Share Posted August 10, 2015 (edited) Clearances! There are lots of them. I knew that from looking at photos, but they only hint at where you need to concentrate - so this post is out of order, but I figure it's worth putting it in. Below is a photo of part of the right hand side of the chassis (it would be a very scary view indeed if it were a full size loco!) the red circles are areas where I've found the tolerances are really close and every one caused me some degree of puzzling about how to keep the wheels turning. It would be better with numbers against the circles, (and better still if they were real circles not impressions of circles from a finger on a trackpad), but I'll do it the old fashioned way, from top to bottom and left to right. Top left: Return crank to eccentric rod, in this pic the eccentric rod is out of position because the motion support bracket isn't lined up properly (more later), but I think it's compounded by my frequent use of additional bosses to get extra depth on the rods. It seems the prototype return crank leans out from the wheel face, whereas this is parallel, so I will fix that. A bit of extra padding on the return crank rivet to push out the eccentric rod would fix this problem, but require more bend on the eccentric rod to align with the motion support bracket, the rod was inadvertently bent in that photo. You could tweak the bends in the eccentric rod between the bosses too.This particular area didn't give me any trouble on the left hand side, though it's *very* close, so I think it'll be OK on the RHS when I'm finished. (Thanks to Dave Holt for useful info regarding this!). Top middle: Motion support bracket and pivot. I found out when investigating clearances that the support bracket wasn't in the vertical plane, it angled in towards the wheels making the radius rod closer to the wheels than it should be. The result is the interference issue already noted with the eccentric rod and return crank, and an additional problem - the connecting rod jams against the expansion link/eccentric rod joint. As you can see, moving the motion support bracket out just a tad (that's a metric tad please), will allow sufficient clearance. This area is very difficult to get a good sight on and I reckon you'd have a fair bit of wiggle room to line things up before anything looked really wrong. Top right: As warned by Dikitriki, the front crank bush can get pretty close to the connecting rod. Dikitriki recesses his which I'd love to do, but I think I'm too scared without a drill press, and don't need to as long as it stays locked on. If it unscrews even a few threads it works very well as an emergency brake... Bottom right, middle bottom and penultimate bottom left: I've mentioned the brake brackets and buckles before - they were just catching the coupling rods. I hope you can just make out some 10 BA washers put under the top hat bushes to space the coupling rods away from the wheel faces and hence the brake buckles. This is probably a non-issue now it's been pointed out to me that O-finescale has so much slop betwen the wheels and rails that you don't really need any sideplay, I had a lot left in at this point and I will get rid of it in due course. Just a word of caution: the buckles are set into etched recesses in the chassis and I spent quite a bit of time fettling them to try and get the soldered sides to seat properly in the recess (they are still proud of the chassis as per the prototype). If you were a little sloppy with that, they would stick out further and be more likely to cause interference. Bottom left: Finally the pivot pin area of the rear coupling rod. My extra 10BA washers also sorted this one out, without them, the boss just touched the raised part of the wheel face. Wishing you sweet running. Did I mention the chassis will run on a 1.5V battery? Admittedly only with the LHS motion in place, but still, that's better than I thought possible and bodes well for nice slow running once in a while. Edited August 15, 2015 by Tim2014 Link to post Share on other sites More sharing options...
Tim2014 Posted August 10, 2015 Author Share Posted August 10, 2015 Tis flood or drought from me! While I'm here, I'd be interested in what you think of the following video of my dabblings with smoke: password is: 46159 This is just a first prototype, I can definitely get a variant of it in the smokebox/boiler, but I will need an opening smokebox door, and yes, in the interests of getting this loco finished, you should probably tell me it's rubbish! Link to post Share on other sites More sharing options...
Guest Isambarduk Posted August 10, 2015 Share Posted August 10, 2015 "max sideplay (I forget what mine is, I set it based on needing to negotiate 2 m radius curves)."Tim, despite what most RTR and kit manufactures may think, with a six-coupled loco in 0 Fine Standard, you don't need any significant sideplay in the axles at all - just sufficient end float to prevent the hornblocks jamming in the hornguides/frames. There is so much slop between wheel flanges and the 32mm gauge in 0F that there is more than enough to be taken up by a curve of only 2m radius. If you do want to push locos round tighter radii then the solution is the same as for the prototype: gauge widen. Just to illustrate the point, here is a RTR 8F that I extensively reworked, including taking out all the slop in the axles to leave just a few thou of end float, and it traverses 6' radius curves with ease. Please see www.davidlosmith.co.uk/LMS_8F.htm for captioned pictures of the details.There are thumbnails and links to more examples at: www.davidlosmith.co.uk/railwayengineeringmodels.htm When building my scratch-built and kit-built locos, I push the frames out to 28mm (overall width), which not only improves the appearance (the wheels are close to the frames), it also helps with taking up the excessive slop that is almost always built into kit designs. David Link to post Share on other sites More sharing options...
Tim2014 Posted August 10, 2015 Author Share Posted August 10, 2015 "max sideplay (I forget what mine is, I set it based on needing to negotiate 2 m radius curves)." Tim, despite what most RTR and kit manufactures may think, with a six-coupled loco in 0 Fine Standard, you don't need any significant sideplay in the axles at all - just sufficient end float to prevent the hornblocks jamming in the hornguides/frames. There is so much slop between wheel flanges and the 32mm gauge in 0F that there is more than enough to be taken up by a curve of only 2m radius. If you do want to push locos round tighter radii then the solution is the same as for the prototype: gauge widen. Please see www.davidlosmith.co.uk/LMS_8F.htm for captioned pictures of the details. There are thumbnails and links to more examples at: www.davidlosmith.co.uk/railwayengineeringmodels.htm When building my scratch-built and kit-built locos, I push the frames out to 28mm (overall width), which not only improves the appearance (the wheels are close to the frames), it also helps with taking up the excessive slop that is almost always built into kit designs. David Thanks David - I forgot the wheel flanges aren't necessarily a good a fit between the raiI'll edit that post above, I've definitely built in more sideplay than I need. That's great news and I think from memory means I can get two etched spacers between the hornblock and the wheel. I'm also pretty sure I'm going to have to relay my track to get this loco to run on it round the curves. I'm pretty certain that spacing out the frames would be beyond me at this point, but that's definitely something I'll think about for other builds. Your link is full of other great ideas. I need to get me some of that 'black hose'. And find some miniature rare earth magnets too, I got some 1mm, but they are still a bit big I think. Your 'big end' solution is pure genius! A great improvement on the stock loco I must say (and very helpful as I have some injector pipework in store on this). Link to post Share on other sites More sharing options...
Grasshopper John Posted August 10, 2015 Share Posted August 10, 2015 Tim, I used 145 solder on my return cranks and 188 on the eccentric rod joint, BUT you have to be quick and use a lot of flux ( as I found out ) I hope you can see the bends I put on the return crank from this It needs two small bends, one to keep it clear of the coupling rod and another to keep the eccentric rod clear. It's a lot of work though, and trial and error. HTH John. 1 Link to post Share on other sites More sharing options...
Dave Holt Posted August 10, 2015 Share Posted August 10, 2015 (edited) "Top left: Return crank to eccentric rod, in this pic the eccentric rod is out of position because the motion support bracket isn't lined up properly (more later), but I think it's compounded by my frequent use of additional bosses to get extra depth on the rods. I don't know the the return crank is parallel to the wheel face on the prototype, a small deflection out, and/or a bit of extra padding on the return crank rivet to push out the eccentric rod would work. I suppose you could also add a slight bend in the eccentric rod.This particular area didn't give me any trouble on the left hand side, though it's *very* close, so I think it'll be OK on the RHS when I'm finished. Top middle: Motion support bracket and pivot. I found out when investigating clearances that the support bracket wasn't in the vertical plane, it angled in towards the wheels making the radius rod closer to the wheels than it should be. The result is the interference issue already noted with the return crank, and an additional problem - the connecting rod jams against the expansion link/eccentric rod joint. As you can see, moving the motion support bracket out just a tad (that's a metric tad please), will allow sufficient clearance. This area is very difficult to get a good sight on and I reckon you'd have a fair bit of wiggle room to line things up before anything looked really wrong." Tim, On the real thing, the return crank was not parallel with the rods but sloped outwards slightly from crank pin to eccentric rod. The eccentric rod was kinked at the two bosses. At the return crank end, the eccentric rod centres were 7' - 8 3/4" but at the expansion link frame, only 7' - 7". So the rods do taper in towards the front, though perhaps not as sharply as your model? Dave. Edited August 10, 2015 by Dave Holt Link to post Share on other sites More sharing options...
Tim2014 Posted August 15, 2015 Author Share Posted August 15, 2015 (edited) I've definitely made the radius rods a lot more complicated than they need to be and I'm not sure the extra detail is really worth the effort. Some scrap N/S and a Ragstone rivet. These are going to form the slide (dunno what it's proper name is) and pivot between the reversing arms and the radius rod: There's not much material to work with so I drilled a small location hole in the smaller piece, then add one and drill it out once joined. Finally repeat with the last face. Once all 3 are soldered together you drill out to the diameter of the rivet and file the faces square. Next, desolder, clean up the faces and resolder the slide together around the radius rod. You've nice tinned faces and I would recommend no flux at this point, line it up and get in and out quickly. Nearly there, just chop off the excess rivet and solder it to the back face of the reversing lever arm to hold everything together. I would recommend using a lower temp solder for this last joint, I used 145 and even though it was the tiniest amount of flux, I found it had seized up solid. If you use a lower temp, at least you can get the thing apart without wrecking all your previous work. I was lucky and a bit of heat meant I could get it just free enough to keep it moving as the solder set and that was then enough to gradually work the joint free again. The combination lever is straightforward (except that I managed to put this sides on back to front and realised just as I'd added the connecting link and 'finished' that side!), I chose to double laminate mine since there are spares on the etch. I also decided to double laminate the connecting link and to get nice looking joints then means you have to file just over half an etch off each inner face of the link, and off each outer face of the combination lever: Solder together: Then join the crosshead link to the combination lever. I still need to file away the outer faces a bit, but that can happen another day, I was impatient to make sure the motion all works. The nuts are just filed brass circular spacers that are provided in the kit. A bit of brass rod then goes through the 'nut' and is soldered in place. I solder the inside face of the valve gear to the end of the rod to make the joint pivot. Here's the dreaded valve guide castings, still not perfectly lined up, but a darn sight better than it would have been if I'd assembled it as provided. This is a rubbish photo, but it's far and away the most complex piece of model machinery I've ever assembled: A quick look at where I'm planning to head with the connection between return crank and eccentric rod. I know you can get nice detail parts for these, but this is cheap and I did it myself. Does anyone know what size the prototype pins were? I'd like to add them, but they might be so fine I could pretend they are invisible I think it needs a bigger washer and a smaller nut, this was a 10BA washer with a 12BA nut. I think 14BA will be about right for the nut. The rivet and nut are tapped so that they actually function as intended using paint/nail varnish in lieu of a pin. The good news is that I had a powered run today with the full valve gear fitted. It runs very nicely, there are some slight tight spots, but they aren't enough to show up under power. When I next take the motor out, I'll see whether I can sort them. I have another boss to add to complete the LHS eccentric rod and then the valve gear is pretty much done and I can finish off the cylinders. The kit box is a LOT lighter now! Finally here's a revisited pic of the RHS from underneath: Edited August 15, 2015 by Tim2014 8 Link to post Share on other sites More sharing options...
Tim2014 Posted September 4, 2015 Author Share Posted September 4, 2015 (edited) After all the fiddling with tiny bits of valve gear, it was a nice change to finish off the cylinders which were pretty straightforward, the only problem being clearance between the piston rod and the cylinder cover, I chopped the casting down a bit: I probably should have bent the drain cock piping down at the tips before fitting it and will probably just leave it straight now (it still needs trimming shorter). There seems to be a lot of variation on the real things depending on the time of the photos and the actual loco - I expect they regularly got clobbered in service, hopefully at some point they might have been straight: I’ve still to do a few bits and bobs on the chassis (like injectors), but want to get onto something substantial so decided to get going on the body. I was able to jump a lot of the instructions now since I’d already done a fair bit of work on the footplate. The cab is the next order of unfinished business, here are the parts on the etch and cut off: The roof rolled OK, although the ventilator etched outline stayed flat. I will drill and cut it out, but with the cover in place I don't think it will be noticeable (the photos of the shiny brass highlight distortions): I was concerned about going from the curved cab roof into crisp cab sides. With so little metal above the window frames, that proved to be justified, and I had to resort to creative use of steel rules and mole grips to squish everything flat (ish) as the side above the window preferred the contour of the roof. My metal folding pliers didn’t have the depth to get up into the quite narrow space where the roof becomes the cab side: This is what happens when you forget where the jaws are on the other side I managed to press it back into shape, brass is really very forgiving! It was at this point I realised I'd soldered the cab front in too hastily and didn’t quite get it square. I contemplated completely redoing it, but in the end bending, twisting and tweaking got everything square enough to sit flat on the footplate and I could then bend the cab entrance sides in and out. It took a good evening, but in the end you end up with a big chunk of loco – not exactly finished – but certainly formed. I’m still not convinced my annealing technique is good enough. ‘Etched loco construction’ talks about the dangers of making the brass too soft, well, I can’t see that happening. I do have a weedy pencil flame though and probably should get a real blow lamp. I’m really enjoying the build making such rapid progress (and when I drop something the size of the cab, it’s easy to find – unlike cursed 14BA nuts!). The cab needed only a small broadening of the radiuses at the bottom front to sit nice and square against both angles of the footplate. I’ve decided not to fix it down just yet, I want to have my options for adjustment open so will wait until the whole boiler assembly is together before committing to securing the cab. As an aside, late that night I couldn’t resist trying the firebox former up against the cab front and must have spent a full 20 mins wondering how on earth I’d bodged the cab up so badly: the firebox sat completely wrong – overlapping the windows for goodness sake: Turns out I was using the front former instead of the back one…doh! Up next is the firebox itself, what could possibly go wrong? Edited September 4, 2015 by Tim2014 Link to post Share on other sites More sharing options...
Tim2014 Posted September 4, 2015 Author Share Posted September 4, 2015 (edited) I confess to having identified the firebox as the hardest part of the build after the CSB and general hardships of a coupled chassis, all those compound curves and in such a visible location. Here are the bits once the (incredibly rigid) cage has been put together: I studied the instructions long and hard, cleaned up all the bits and scored ‘bend’ areas on the inside to show where I needed the brass to be nicely annealed: Learning from the cab front, I spent a while with a tacked face getting it dead centered and square: Wrapping the sides around put bends in roughly the right place but there was still a lot of spring in the metal (EDIT: my annealing again? I originally used a micro flame to try and anneal this and it's just not up to the job. Use a blow lamp and get it good and hot for a minute or so, it makes the wrapping a much simpler process) and forcing in the reverse flares at the bottom of the firebox was *hard* work. Still, after another full evening, sore fingers and quite a few solder failures (the tacks just couldn’t hold the metal as I forced it) I had something I was happy with: Amazingly, all the cage spacers came out easily and the assembly even fitted the chassis reasonably well (this is the best side): I think a little will need to come off the bottom and the rear face, but the instructions alluded to that so all is hopefully well: With the cab and firebox sitting on the footplate, the hulking bulk of the loco that I love so much is starting to become apparent. EDIT: Properly annealing the wrapper after desoldering it (but not altering it's old shape), meant I could form it to near mm perfect fit before reaching for the soldering iron.I stand by this being the hardest part of the build though. The brass is very thick and even though I think I got the temp up to just below red hot, it was very hard to work and required a lot of force and judicious choice of formers to use to get the reverse curves in at the base. I remembered the ‘damp paper towel’ midway through and this works really well as nothing conforms to a complex curve like a thumb over some damp kitchen towel. It allows pressure in exactly the right place while you can apply the iron, get the solder flowing and have time to let the joint cool. If (when!) I do another, I would seriously consider desoldering the tacks once the top bends are done and then taking the wrapper off the end plates to complete the folds (bending past the former outline to allow the metal to spring back to almost the exact shape. You’d then retack in position and work out where the reverse folds go. Slower, but I think the finished result would be neater and easier on the old hand muscles too. I'm sure the precision folk could work out exactly where each bend should go and could fold it up off the cage, I know trying to do that myself would end in disaster! EDIT: Here is the wrapper after desoldering, annealing properly and then finishing the forming off the cage: Needless to say that soldering this onto the cage was MUCH easier than first time around. The damp paper towel is still a handy accessory though Edited September 13, 2015 by Tim2014 2 Link to post Share on other sites More sharing options...
3 link Posted September 4, 2015 Share Posted September 4, 2015 Hi Tim, You really do need to get a blow lamp or a gas hob to spread the heat more evenly, as the small flame you are using is leaving the metal in various stages of strength and stresses if you get my drift. It is OK to have a little bit of spring as you press and solder the sheet around the former, but you do not want to have to use to much force in case of failure later on in the build or even once painted and running. HTH, Martyn. Link to post Share on other sites More sharing options...
Tim2014 Posted September 4, 2015 Author Share Posted September 4, 2015 Hi Tim, You really do need to get a blow lamp or a gas hob to spread the heat more evenly, as the small flame you are using is leaving the metal in various stages of strength and stresses if you get my drift. It is OK to have a little bit of spring as you press and solder the sheet around the former, but you do not want to have to use to much force in case of failure later on in the build or even once painted and running. HTH, Martyn. Thanks Martyn, Point taken - I'm off to the local hardware store to get one this weekend! I applied a bit of Science and had a go at the Smokebox wrapper on a ceramic pizza stone, heating to 250C + with the hood closed, then taking the pencil flame to it (I have a laser themometer which maxes out at 500C so I figured that needed to be maxed out at a minimum). I played the pencil over the upper surface and could see it glowing dimly (it was dark, with a bit of artificial light). When I'd delicately got it off the stone and quenched it, I could see the top face looked annealed, but the bottom face (next to the ceramic) was still shiny apart from the occasional obvious hot spot. I think there is just too much convection and conduction on a large piece like the firebox and smokebox (and even cab roof I think, but that only has a constant, gentle radius so I got away with it) to allow the heat to rise high enough, for long enough, to really get the metal annealed properly. There's no danger of the firebox coming unstuck now it's seamed, but I know I could do it slightly better and that bugs me, so depending on how the smokebox goes with a proper heat source, I may redo the firebox. I'll find a thick and thin piece of sheet to practice with first - I want to see just how soft I can make the brass - I hate the idea of a set of finger holes in what was a half-decent part of a loco! A couple of jewelry sites imply that although annealing softens the brass, it's still relative and doesn't turn to butter. Like many arts - I suspect this aspect of metal work is something that becomes so obvious with a bit of experience that no-one thinks to tell anyone else, especially on the web. Maybe if I ever master it I'll do some nice colour photos of different bits of brass after heating to various temps to help the next poor newb. Link to post Share on other sites More sharing options...
JeffP Posted September 5, 2015 Share Posted September 5, 2015 Hang on, isn't annealing in brass done by heating/allowing to cool slowly? I thought quenching was for re-hardening? Just checked and it seems you can do both. My old metalwork teacher wouldn't have approved. Link to post Share on other sites More sharing options...
Deano747 Posted September 5, 2015 Share Posted September 5, 2015 Hang on, isn't annealing in brass done by heating/allowing to cool slowly? I thought quenching was for re-hardening? Just checked and it seems you can do both. My old metalwork teacher wouldn't have approved. Yes both methods work, surprisingly?! Brass, unlike steel, does not harden this way. The only way to harden brass is by 'working' it. Regards, Deano Link to post Share on other sites More sharing options...
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